1. Field of the Invention
The invention relates to tunable high-frequency devices based on superconductive materials.
2. Discussion of Background
A device for the processing of electromagnetic waves may be formed by an element made of a superconductive material as well as a dielectric element associated with this superconductive element.
Since the thickness of an element made of superconductive material is smaller than the length of penetration .lambda..sub.L of the magnetic field, the device has an additional inductance, known as a kinetic inductance, due to the superconductive element, and this kinetic inductance gets added to the ordinary magnetic inductance.
This inductance takes account of the kinetic energy of the superconductive electrons. For very thin layers, it is proportional to the square of the depth of penetration .lambda..sub.L of the magnetic field and hence inversely proportional to the Cooper pairs density.
For a determined Cooper pairs density, the kinetic inductance is fixed.
The invention provides for means enabling the modification, at will, of the additional kinetic inductance. For this purpose, these means are such that they enable the modification of the Cooper pairs density.
This Cooper pairs density may be changed by:
the variation of the temperature; PA0 the application of a polarization current; PA0 the application of a magnetic field; PA0 the illumination of the superconductor by a radiation.